Received November 10, 2014; Revision received December 8, 2014
Previous studies showed that large amounts of phenylcarboxylic acids
(PhCAs) are accumulated in a septic patient’s blood due to
increased endogenous and microbial phenylalanine and tyrosine
biotransformation. Frequently, biochemical aromatic amino acid
transformation into PhCAs is considered functionally insignificant for
people without monogenetic hereditary diseases. The blood of healthy
people contains the same PhCAs that are typical for septic patients as
shown in this paper. The overall serum PhCAs level was 6 µM
on average as measured by gas chromatography with flame ionization
detection. This level is a stable biochemical parameter indicating the
normal metabolism of aromatic amino acids. The concentrations of PhCAs
in the metabolic profile of healthy people are distributed as follows:
phenylacetic ≈ p-hydroxyphenyllactic >
p-hydroxyphenylacetic > phenyllactic ≈ phenylpropionic
> benzoic. We conclude that maintaining of stable PhCAs level in the
serum is provided as the result of integration of human endogenous
metabolic pathways and microbiota.
KEY WORDS: tyrosine metabolism, sepsis, phenylcarboxylic acids,
phenyllactic acid, p-hydroxyphenyllactic acid, phenylpropionic
acid, benzoic acid, microbiota